The present invention is a supply unit for delivering fluids. Such supply units generally have an internal gear pump, as a pump unit, with a bearing race in which a driven inner gear is arranged on a bearing journal. An outer gear, arranged between the inner gear and the bearing race, rotates with the inner gear by way of toothing. The inner gear has one tooth fewer than the outer gear so that a pumping action is produced.
WO 92/15 785 A1 shows a supply unit for delivering fluids in which the pump unit is an internal gear pump. The internal gear pump, also known as a "gerotor" consists of a bearing race in which an inner gear is rotatably arranged on a bearing journal. The bearing journal, and with it the inner gear, is driven by a motor. An outer gear is arranged between the inner gear and the bearing race and is rotated by, and with, the inner gear. The inner gear is provided with one tooth fewer than the outer gear, so that a pumping action is produced. All parts of the internal gear pump, such as the bearing race, inner gear and outer gear, consist of metal.
In the above-mentioned WO 92/15 785 A1, at least parts of the multi-part pump housing are produced from a ceramic material. It is intended that the generation of noise should thereby be reduced.
EP 0 464 261 A1 shows a supply unit, especially for delivering motor fuel, with an electric drive motor and a pump unit ("gerotor") coupled thereto which comprises a base plate, an intermediate plate with a cut-out for the rotating pump parts, and a cover. In this case at least the base plate and the cover consist of a ceramic material, the end faces, nearer the intermediate plate, of the base plate and of the cover having ground surfaces.
Objectives underlying the present invention include constructing a supply unit of the above generally described type so that it has a low noise level and is corrosion-resistant. An additional objective is to provide a supply unit having a reduced weight.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects obtained by its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention .